The present invention relates to a footwear structure incorporating a heating device, particularly for ski boots.
An earlier patent by the same Assignee (U.S. Pat. No. 4,507,877) discloses a heating device, particularly for ski boots which comprises an inner ski boot, including a printed circuit electrical resistance heater and rechargeable storage batteries incorporated at a sole region thereof, and a plug, located at the upper portion of the inner ski boot which is adapted for connection to a source of electrical power for the purpose of re-charging the storage batteries.
Also known, for example from a further prior published patent application by the same Assignee (Italian Application No. 20890 B/83, filed on Feb. 22, 1983) is a heating device for ski boots which comprises a sock having a printed circuit electrical resistance heater at a sole portion thereof, a container, including rechargeable storage batteries and a plug, adapted for connection to a source of electrical power for re-charging the batteries.
The cited prior patent by the same Assignee (U.S. Pat. No. 4,507,877) also deals with a heating device for ski boots. This prior application primarily concerns the provision of a limiting device in an electrical resistance heating circuit, to prevent rechargeable storage batteries being over-charged, or completely exhausted, thereby rendering them unrechargeable. The device also comprises a socket for connecting a ski boot, to a source of electrical energy for recharging the storage batteries incorporated therein.
Furthermore, in another earlier published patent application by the same Assignee, (Italian Application No. 21947 B/84, filed on May 29, 1984) a ski boot is disclosed including an internal heating device which also incorporates a printed circuit electrical resistance heater and rechargeable storage batteries. The device further comprises a socket adapted for connection to a domestic power supply via a lead equipped with suitable plugs, for the purpose of recharging the batteries.
Such known ski boot structures however, are not exempt of drawbacks, which reside in the fact that such ski boots have to be taken proximately to a source of electrical energy, in order for the storage batteries incorporated therein to be recharged. Thus, after use, when the storage batteries need to be recharged, the ski boots, which frequently become soiled and wet must be taken indoors and connected to a source of electrical energy.
These prior arrangements, whilst being inconvenient, not least from the standpoint of cleanliness, incur a further serious disadvantage from the standpoint of safety, due to the fact that the ski boot, which may be wet, must be connected to a source of electrical energy and may therefore, inadvertently become a dangerous conductor of such energy.
Another inconvenience of these prior types, is that the ski boots cannot be used whilst the storage batteries are being recharged.